1. Field of the Invention
The subject application generally relates to a communication system, and more specifically, to a communication system with high communication quality.
2. Description of the Related Art
With the advancement of mobile communication technology, mobile devices such as portable computers, mobile phones, multimedia players, and other hybrid functional portable electronic devices have become more common. To satisfy the demand of users, mobile devices usually can perform wireless communication functions. Some devices cover a large wireless communication area; these include mobile phones using 2G, 3G, and LTE (Long Term Evolution) systems and using frequency bands of 700 MHz, 850 MHz, 900 MHz, 1800 MHz, 1900 MHz, 2100 MHz, 2300 MHz, and 2600 MHz. Some devices cover a small wireless communication area; these include mobile phones using Wi-Fi and Bluetooth systems and using frequency bands of 2.4 GHz, 5.2 GHz, and 5.8 GHz.
A current mobile device usually includes multiple antennas and transceivers for good communication quality and multiband operations. While the wireless communication function is performed, the mobile device can dynamically select one antenna which has the best communication quality to the relative base station. However, a conventional multi-antenna system is limited to the antenna structure and the device size, and it may have low radiation diversity, such that the communication quality may tend to be affected by the environment.
“Package correlation coefficient” is one of the evaluation indexes for signal diversity. If the package correlation coefficient is too high, it may represent that the radiation diversity between antennas is insufficient, and the multi-antenna system cannot provide the best communication quality. A conventional multi-antenna system often faces the problem of having a high package correlation coefficient. Accordingly, there is a need to design a new communication system for solving this problem in the prior art.